Anti-inflammatory method

ABSTRACT

Compounds in which 2,6-di(t-butyl)phenol is substituted in the 4 p;osition by an optionally substituted phenyl group have valuable pharmacological activity as anti-inflammatory agents.

This is a division of copending application Ser. No. 861,892 filed Dec.19, 1977, now U.S. Pat. No. 4,172,151, Ser. No. 861,892 being a divisionof copending application Ser. No. 797,137 filed May 16, 1977 (nowabandoned).

BACKGROUND OF THE INVENTION

This invention relates to the use of 2,6-di(t-butyl)-4-phenylphenols asanti-inflammatory agents and to certain novel compounds.

The compound 2,6-di(t-butyl)-4-phenylphenol itself is known (see, forexample, J. Am. Chem. Soc. 95:4698, 1973), and the synthesis of2,6-di(t-butyl)-4-(4'-nitrophenyl)phenol has been reported (J. Org.Chem. 33:1245, 1968). 2,6-Di(t-butyl)-4-phenylphenols in which the4-phenyl ring is substituted by other groups are, however, novel insofaras is known. No physiological use of any of these compounds has beenreported, however.

DETAILED DESCRIPTION OF THE INVENTION

Specifically the invention relates to a method for combattinginflammatory processes in mammalian animals which comprisesadministering thereto an effective dose, less than the toxic amount, ofa compound of the formula: ##STR1## wherein R is selected from hydrogen,amino, alkanamido containing from 2 to 4 carbon atoms,trifluoroacetamido, halogen, methoxy, methyl and 4-nitro. The inventionalso relates to anti-inflammatory compositions comprising one or moresuch compounds (in which R is as just recited) together with a suitablepharmaceutical extending medium. The compounds of formula I wherein R ishydrogen, amino or methoxy are presently preferred for use in theanti-inflammatory method and compositions of the invention, particularlythose in which R is hydrogen, 4'-amino or 2'-methoxy.

In another aspect, the invention relates to new chemical compounds ofstructure I but wherein R is amino, alkanamido containing from 2 to 4carbon atoms or trifluoroacetamido. It is noted that when R is nitro,only the compound wherein R is 4'-nitro has been found to be useful asan anti-inflammatory agent. Novel compounds wherein R is 2'-nitro or3'-nitro form part of the invention, however, since they can be reducedto 2'-amino or 3'-amino compounds which are useful as anti-inflammatoryagents.

In addition to their anti-inflammatory activity, some of these compoundsare also analgesic and antipyretic agents and some have mildimmunosuppressant activity.

In order to determine and assess pharmacological activity, testing inanimals is carried out using various assays known to those skilled inthe art. Thus, the anti-inflammatory activity of the compounds can beconveniently demonstrated using an assay designed to test the ability ofthese compounds to antagonize the local edema which is characteristic ofthe inflammatory response (the rat foot edema test). Anti-inflammatoryactivity may also be detected by other assays known to the art such asthe cotton pellet granuloma test and the adjuvant arthritis test and theinhibition of the enzyme prostaglandin synthetase.

Leading references to the rat foot edema method are:

(1) Adamkiewicz et al, Canad. J. Biochem. Physio. 33:332, 1955;

(2) Selye, Brit. Med. J. 2:1129, 1949; and

(3) Winter, Proc. Exper. Biol. Med. 111:554, 1962.

The edema test is performed on adult female rats. One group of 10 ratsserves as non-medicated controls, while another group of 10 ratsreceives the test compound at various times prior to the induction ofthe edema, usually 15 minutes, one hour and/or 18 hours. The testcompound is administered orally as a suspension in 4 percent aqueoussolution of acacia. Edema is induced by the plantar injection of 0.5percent carrageenin (0.1 ml/foot) into the right hind foot. The lefthind foot receives a like volume of 0.9 percent saline solution. Onehour later, the volume of each hind foot is determinedplethysmographically. The edema is expressed as the increase in thevolume of the edemogen-injected foot (volume of the "edemogen foot" lessthe volume of the "saline foot"). The percent inhibition is calculatedby dividing the mean increase in the edema of the edemogen foot of themedicated group by the mean increase in the non-medicated group,multipled by 100. An active dose is that giving a statisticallysignificant inhibition of the induced edema, usually in the range ofabout 25-35 percent inhibition.

The compounds are preferably administered orally as anti-inflammatoryagents but other known methods of administration are contemplated aswell, e.g. dermatomucosally (for example dermally, rectally and thelike) and parenterally, for example by subcutaneous injection,intramuscular injection, intra-articular injection, intravenousinjection and the like. Ocular administration is also included. Dosagesordinarily fall within the range of about 1 to 500 kg/mg of body weightof the mammal to be treated although oral dosages are not usually above100 mg/kg. Suitable forms for oral administration include liquids (suchas 4 percent acacia and polyethylene glycol solutions), tablets (whichmay contain anhydrous lactose, microcrystalline cellulose, modifiedstarch, calcium stearate and talc, as well as other conventionalcompounding agents together with the active anti-inflammatory agents),solid suspensions and capsules. Suitable carriers for topicalapplication include creams, gels, tapes and the like. Liquidformulations, such as solutions or suspensions of the active ingredientin inert carriers, are contemplated for dosage by injection.

The compounds which are presently preferred for use in the process ofthe invention (due to their high activity in the rat foot edema test)are:

2,6-di-(t-butyl)-4-phenylphenol,

4-(4'-aminophenyl)-2,6-di(t-butyl)phenol and

2,6-di(t-butyl)-4-(2'-methoxyphenyl)phenol.

The preparation of compounds of the invention may be carried out asdescribed in the prior art or by chemical reaction of compoundsdescribed in the prior art. Alternatively, novel compounds of theinvention, for example, compounds wherein R is amino, may be furtherutilized as intermediates to prepare other compounds of the invention.Many compounds of the invention are conveniently prepared by reaction of2,6-di-(t-butyl)benzoquinone with an appropriate Grignard reagent,followed by reduction of the intermediate substituted cyclohexadienone.The necessary starting materials are well known to the art. Thereduction step may be carried out using hydrogen gas and a catalyst suchas palladium on charcoal or Raney nickel, using a metal hydride reducingagent such as lithium aluminum hydride or using hydrogen iodide.

Conventional reactions of aromatic substituent groups are generallyapplicable to the compounds of the invention. For example, nitro groupscan be reduced, amino groups can be acylated, amino groups can bediazotized and replaced and the like.

Preparation of novel compounds of the invention and known compoundsuseful in the method of the invention are described in the followingillustrative examples.

EXAMPLE 1

Magnesium metal (0.55 g.) and 50 ml. of diethyl ether are treated with afew ml. of a solution of 4.25 g. of 4-bromoanisole in 50 ml. of ether.An iodine crystal is added, and the mixture begins to react uponwarming. The remainder of the solution is added, and the mixture isheated at its reflux temperature for 15 minutes. It is then added over30 minutes to a solution of 2,6-di(t-butyl)benzoquinone in 50 ml. ofether. This mixture is heated at its reflux temperature for two hours,then stirred at room temperature for 16 hours. The product is2,6-di-(t-butyl)-4-hydroxy-4-(4'-methoxyphenyl)-2,5-cyclohexadienone.

To this product is added 1.5 g. of lithium aluminum hydride dissolved indiethyl ether. After stirring for 30 minutes, the solution is acidifiedwith 10 percent hydrochloric acid and extracted with dichloromethane.The extracts are dried over magnesium sulfate, then evaporated toprovide an oil which is chromatographed on 125 g. of 60-200 mesh silicagel, eluting with 1:3 benzene-hexane. The first 500 ml. of solvent isevaporated to provide an oil which crystallizes when petroleum ether isadded. Recrystallization from petroleum ether provides2,6-di(t-butyl)-4-(4'-methoxyphenyl)phenol, m.p. 109°-110° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.21 H.sub.28 O.sub.2 :                                                       80.7,      9.0                                             Found:             80.9       9.2.                                            ______________________________________                                    

EXAMPLE 2

Using the method described in the art (J. Org. Chem. 33:1245, 1968)2,6-di(t-butyl)-4-(4'-nitrophenyl)phenol, m.p. 154°-156° C., isprepared. Using this method and starting with 2-chloronitrobenzene,2,6-di(t-butyl)-4-(2'-nitrophenyl)phenol, m.p. 101°-102.5° C. isprepared.

EXAMPLE 3

A solution of 50 g. (0.152 mole) of2,6-di(t-butyl)-4-(4'-nitrophenyl)phenol in 350 ml. of ethyl acetate isreduced with hydrogen gas at about 45 psig in a Paar apparatus using 10percent palladium on charcoal as catalyst. The mixture is allowed tostand for about 16 hours, filtered, and the filtrate evaporated undervacuum. The residue is cooled, dissolved in ethanol and triturated withwater. The resulting off-white solid is recrystallized from petroleumether to provide 4-(4'-aminophenyl)-2,6-di(t-butyl)phenol, m.p.113°-114.5° C.

    ______________________________________                                        Analysis:         % C      % H      % N                                       ______________________________________                                        Calculated for C.sub.20 H.sub.27 NO:                                                            80.7,    9.1,     4.7                                       Found:            81.1,    9.1,     4.7.                                      ______________________________________                                    

EXAMPLE 4

A solution of 10 g. (0.0336 mole) of4-(4'-aminophenyl)-2,6-di(t-butyl)phenol in 50 ml. of dichloromethane isreacted with 7.1 g. (0.034 mole) of trifluoroacetic anhydride. Theimmediate reaction is followed by evaporation of the solvent to providea residue which is recrystallized from a benzene-hexane mixture. Thewhite product is 2,6-di(t-butyl)-4-(4'-trifluoroacetamidophenyl)phenol,m.p. 155°-156° C.

    ______________________________________                                        Analysis:         % C      % H      % N                                       ______________________________________                                        Calculated for C.sub.22 H.sub.26 F.sub.3 NO.sub.2 :                                             67.1,    6.7,     3.6                                       Found:            67.1,    6.7,     3.5.                                      ______________________________________                                    

EXAMPLE 5

A solution of 15 g. (0.050 mole) of4-(4'-aminophenyl)-2,6-di(t-butyl)phenol in 100 ml. of glacial aceticacid is treated with 5.2 g. (0.050 mole) of acetic anhydride. Theresulting solution is heated gently for 10 minutes, diluted with water,cooled, and the solid product is separated by filtration.Recrystallization from a benzene-hexane mixture provides4-(4'-acetamidophenyl)-2,6-di(t-butyl)phenol, m.p. 173°-174.5° C.

    ______________________________________                                        Analysis:         % C      % H      % N                                       ______________________________________                                        Calculated for C.sub.22 H.sub.29 NO.sub.2 :                                                     77.8,    8.6,     4.1                                       Found:            77.8,    8.8,     4.0.                                      ______________________________________                                    

EXAMPLE 6

To a stirred solution of 15 g. (0.0504 mole) of4-(4'-aminophenyl)-2,6-di(t-butyl)phenol in 75 ml. of dichloromethane isadded dropwise 5.37 g. (0.0504 mole) of n-butyroyl chloride. Thereaction is immediate. The solvent is removed by evaporation, and thesolid residue is recrystallized, first from aqueous ethanol, then fromheptane to provide 4-(4'-butyramidophenyl)-2,6-di(t-butyl)phenol, m.p.180°-181° C.

    ______________________________________                                        Analysis:         % C      % H      % N                                       ______________________________________                                        Calculated for C.sub.24 H.sub.33 NO.sub.2 :                                                     78.4,    9.0,     3.8                                       Found:            78.4,    8.9,     3.7.                                      ______________________________________                                    

EXAMPLE 7

Using the method described in Example 1, 2-bromomethoxybenzene isreacted with 2,6-di(t-butyl)hydroquinone to provide2,6-di(t-butyl)-4-hydroxy-4-(2'-methoxyphenyl)-2,5-cyclohexadienone.This product is dissolved in ethanol and reduced with hydrogen gas on aParr apparatus using palladium on charcoal as the catalyst. The whitesolid product is recrystallized from benzene to provide2,6-di(t-butyl)-4-(2'-methoxyphenyl)phenol, m.p. 98.5°-100° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.21 H.sub.28 O.sub.2 :                                                       80.7,      9.0                                             Found:             81.1,      9.1.                                            ______________________________________                                    

EXAMPLE 8

Using the method of Example 7, but starting from 3-bromomethoxybenzene,one obtains 2,6-di(t-butyl)-4-(3'-methoxyphenyl)phenol, m.p. 96°-98° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.21 H.sub.28 O.sub.2 :                                                       80.7,      9.0                                             Found:             80.9,      9.2.                                            ______________________________________                                    

EXAMPLE 9

Using the method of Example 1, but starting from 2-bromotoluene, oneobtains2,6-di(t-butyl)-4-hydroxy-4-(2'-methylphenyl)-2,5-cyclohexadienone, m.p.168°-171° C. This product is reduced as described in Example 7 toprovide 2,6-di(t-butyl)-4-(2'-methylphenyl)phenol, m.p. 85.5°-87.5° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.21 H.sub.28 O:                                                              85.1,      9.5                                             Found:             84.7,      9.5.                                            ______________________________________                                    

EXAMPLE 10

Using the method described in Example 1, 4-bromofluorobenzene is reactedto provide2,6-di(t-butyl)-4-hydroxy-4-(4'-fluorophenyl)-2,5-cyclohexadienone, m.p.123°-125° C. This product is reduced as described in Example 1 toprovide 2,6-di(t-butyl)-4-(4'-fluorophenyl)phenol, m.p. 97°-99° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.20 H.sub.25 FO:                                                             80.0,      8.4                                             Found:             79.7,      8.5.                                            ______________________________________                                    

EXAMPLE 11

Using the method of Example 7, 4-bromotoluene is converted to2,6-di(t-butyl)-4-(4'-methylphenyl)phenol, m.p. 119.5°-121° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.21 H.sub.28 O:                                                              85.1,      9.5                                             Found:             85.2,      9.5.                                            ______________________________________                                    

EXAMPLE 12

Using the method of Example 1, 2-bromochlorobenzene is reacted toprovide 2,6-di(t-butyl)-4-(2'-chlorophenyl)-2,5-cyclohexadienone. Thisproduct (5.0 g., 0.015 mole) is treated with 125 ml. of concentratedhydroiodic acid and stirred for about 16 hours. The mixture is filtered,the residue rinsed with water and then dried to provide an off-whitepowder. The product is recrystallized from petroleum ether to provide2-(2'-chlorophenyl)-2,6-di(t-butyl)phenol, m.p. 89.5°-91° C.

    ______________________________________                                        Analysis:           % C       % H                                             ______________________________________                                        Calculated for C.sub.20 H.sub.25 Cl0:                                                             75.8,     7.95                                            Found:              76.1,     8.1.                                            ______________________________________                                    

EXAMPLE 13

To a solution of 7.0 g. (0.0235 mole) of b4-(4'-aminophenyl)-2,6-di(t-butyl)phenol in 3 ml. (0.0706 mole) ofconcentrated sulfuric acid is added about 15 ml. of water, and themixture is chilled to about 5° C. To this mixture a cold solution (about5° C.) of 1.62 g. (0.0235 mole) of sodium nitrite in 8 ml. of water isadded dropwise with stirring. The mixture is stirred for another tenminutes, and a cold solution of 3.37 g. (0.0235 mole) of cuprous bromidein 20 ml. of 48 percent hydrobromic acid is added slowly. After stirringfor an additional hour, the mixture is extracted with about 100 ml. ofdichloromethane. The extracts are dried, then evaporated. The residue ismixed with heptane, then filtered to provide a solid product which ispurified by dissolving in hexane, eluting through a silica gel columnwith methanol-water and recrystallized from petroleum ether. The productis 4-(4'-bromophenyl)-2,6-di(t-butyl)phenol, m.p. 139.5°-141° C.

    ______________________________________                                        Analysis:          % C        % H                                             ______________________________________                                        Calculated for C.sub.20 H.sub.25 BrO:                                                            66.5,      7.0                                             Found:             66.6,      7.2.                                            ______________________________________                                    

What is claimed is:
 1. A method for combatting inflammatory processes ina mammal which comprises administering an effective dose less than thetoxic amount of a compound of the formula ##STR2## wherein R is selectedfrom halogen, methoxy, methyl and 4-nitro to said mammal.
 2. A methodaccording to claim 1 wherein R is methyl.
 3. A method according to claim1 wherein R is 4-nitro.
 4. A method according to claim 1 wherein R ismethoxy.
 5. A method according to claim 1 wherein R is fluoro.